Otis with his band in 1950. He had 10 top 10 R&B hits that year but found himself sidelined by the early 1960s. Photograph: Michael Ochs Archives/Getty

The bandleader Johnny Otis, who has died aged 90, was one of the first white American musicians to cross the racial divide, aligning himself with the black community as a teenager and from then on regarding himself – and being treated as – a black man. He attracted many nicknames – among them the Duke Ellington of Watts, the Reverend Hand Jive and the Godfather of Rhythm and Blues – and distinguished himself as a television host, political activist, preacher, cartoonist, painter, chef, record producer, talent scout, DJ, sculptor, writer and organic farmer.

The economic constraints that followed the second world war helped Otis develop a distinctive style: "I found that when I was playing big band, now and then we'd play a boogie or blues and that's when the people really came to life. When I had to trim my band down, I kept two saxophones, trumpet, trombone. I added a blues guitar, a boogie-woogie piano player and drummer cracking that afterbeat. That's what the people liked."

He signed the 13-year-old Esther Phillips as vocalist for his California Rhythm and Blues Caravan touring show in 1949. With Little Esther singing, he scored 10 top 10 R&B hits in 1950. His one US pop crossover hit came in 1958 with Willie and the Hand Jive, and in the UK he scored a No 2 hit in November 1957 with Ma, He's Making Eyes at Me.

Otis was responsible for either discovering or producing some of America's most potent R&B singers. While scouting for King Records in the early 1950s, he encountered Jackie Wilson, Little Willie John and Hank Ballard at a talent show in Detroit, and they went on to appear in the Caravan.

He produced – and played drums on – Big Mama Thornton's first recordings, including the R&B hit Hound Dog (1953). He was also initially credited as one of the song's composers, though when Elvis Presley covered the song in 1956, Jerry Leiber and Mike Stoller succeeded in having his name removed.

Otis also produced all the hits of the R&B star Johnny Ace, who died in a self-inflicted gunshot accident in 1954, the year in which Otis signed Etta James. They co-wrote her first hit, Dance with Me, Henry (1955), which became a bigger hit for Georgia Gibbs. Otis's Every Beat of My Heart had to wait seven years to become a hit for Gladys Knight in 1961. By the early 1960s, Otis found himself sidelined: "A lot of things, including the Beatles, came along, and we were out of it. We couldn't even get a gig."

Otis was born John Veliotes to Greek immigrants in Vallejo, northern California. He was raised in an ambitious family – his younger brother, Nicholas, eventually became ambassador to Egypt. His parents ran a grocery store in a black neighbourhood in Berkeley, and the teenage Otis chose to walk away from white culture. Black America, he wrote, possessed "soul", a quality he found lacking elsewhere. Having taken up the side drum in junior high school, he made his professional debut in 1939 with the West Oakland Houserockers before going on the road, playing in touring big bands.

Nat King Cole recommended he move to Los Angeles in 1943 to join Harlan Leonard's jazz orchestra. He backed the saxophonist Lester Young and the singer-pianist Charles Brown. As a drummer, Otis led his own jazz orchestra from 1945 to 1948. His 1945 recording Harlem Nocturne proved a strong enough seller to get the band bookings across the US, including a stint at the Apollo theatre in Harlem.

Once the band's work had run its course, Otis became more involved in community work in South Central Los Angeles. A publisher's editor saw a letter that he had sent to a friend about the Watts riots of 1965, and he was invited to write Listen to the Lambs (1968), a meditative book that jumped back and forth between his life in music and his political views.

Though Otis failed to be elected to the California state assembly, he did join the Los Angeles County Democratic committee and served for a decade as deputy chief of staff to Mervyn Dymally, the first black state senator in the west, and an eventual lieutenant governor of California and congressman.

However, Otis missed music. Frank Zappa, a fan of Otis's 1950s recordings, suggested to Kent Records that he had a comeback in mind, and that they should sign him. The resulting album, Cold Shot! (1969), featured Country Girl, an R&B hit, and was a critical success. Otis then recorded an X-rated album, featuring proto-gangsta rap braggadocio. Zappa landed Otis and his musicians a TV appearance that led to a performance at the 1970 Monterey jazz festival.

His revived California Rhythm and Blues Caravan – featuring Little Esther and Otis's teenage, guitar-playing son Shuggie – was a huge success at Monterey, leading to nationwide and European bookings. Otis continued to tour and record, and in 1978 opened and served as pastor for the Landmark Community Church in South Central Los Angeles, his main focus.

In 1990 Otis and his wife, Phyllis, moved to Sebastopol, northern California, where they ran an organic orchard. He hosted a weekly radio programme, wrote his autobiography, Upside Your Head! (1993) and appeared at festivals with a 13-member lineup. Ace Records have recently released two CDs devoted to The Johnny Otis Story. He is survived by Phyllis, two sons and two daughters.